Thread: Program calculation problems?

Hi Guys,

Wondering if anyone can help. Trying to create a simple program which:

- Inputs the price of presents bought

Now when the user has finished entering the price of all the presents bought (they press 0) it:

- Outputs a count of the presents bought
- Outputs a count of the total price of all the presents added up
- Outputs out the average price of the presents bought

Now I have got the program to run, but it does not output the correct information as shown below – can anyone please advise?

http://www.thisisslough.com/c_plus.jpg

Here is my code:

presents.h

Code:

// PRESENTS.H
// Program for calculating Christmas Presents bought
#include <iostream>
using namespace std;
#include<iomanip>
#include <string>

class christmas_presents
	{
   public:
   	  void calculate_average_price() ;
   	  void display_presents_bought() ;
   	  void display_presents_spent() ;
   	  void display_average_price();

   private:
   int present_price;
   int number_of_presents;
   int total_present_price;
   int average_price;
   };

void christmas_presents:: calculate_average_price()
{
char terminator;
cout << "Please input the first price of the present (or 0):";
cin >> present_price;
int number_of_presents = 0;
int total_present_price = 0;
int average_price = 0;
while (present_price !=0)
   {
   total_present_price =+ present_price;
   ++ number_of_presents;
   cout << "Please input the next price of the present (or 0):";
   cin >> present_price;
   }
cin.get (terminator);
if (number_of_presents > 0)
   average_price = total_present_price / number_of_presents;
else
  average_price = 0;
}

void christmas_presents:: display_presents_bought()
  {
  cout <<"You have bought: " << setprecision(2) << number_of_presents << " presents" <<endl;
}

void christmas_presents:: display_presents_spent()
  {
  cout <<"You have spent: " << setprecision(2) << total_present_price << " pounds" <<endl;
}

void christmas_presents:: display_average_price()
  {
  cout <<"On average you have spent: " << setprecision(2) << average_price <<endl;
}

Main program to get it to run

Code:

// ASSIGN78.CPP
// A Program to display christmas presents
#include "presents.h"
#include <cstdlib> 
int main ()
	{
    christmas_presents price;
    price.calculate_average_price ();
    price.display_presents_bought ();
    price.display_presents_spent ();
    price.display_average_price ();
    system ("pause");
	}

- Also at the moment it only seems to let you input whole numbers?

Can anyone please advise – I’d be most greatful?

Many Thanks

Cbo

Thanks guys,

Got it working now apart from entering decimal places.

Say I enter a whole number it works fine, but if I enter 3.50 for example, it throws a wobbily!

I set double average_price;, but it still does let me put in decimal places?

Thanks

Cbo

I set double average_price;, but it still does let me put in decimal places?

Every variable in your program that is assigned a value with decimal places has to be a double or else the decimal part will get chopped off.

Aggh,

I see thanks for your help!

Just one last thing. When it comes to outputting what has been spent it does not output it to 2 decimal places, even though I have made total_present_price and average_price doubles and setprecision(2) on my output as shown below ?

Code:

  cout <<"You have bought: " << setprecision(2) << number_of_presents << " presents" <<endl;
  cout <<"You have spent: " << setprecision(2) << total_present_price << " pounds" <<endl;
  cout <<"On average you have spent: " << setprecision(2) << average_price <<endl;

Say I input 13.00 then 12.00 and press 0 it just says:

You have spent: 25 pounds (Not 25.00, which is what I want it to do)

On average you have spent: 13 pounds (Not 13.00, which is what I want it to do)

Any ideas please?

Ta

Cbo

Code:

cout <<"You have spent: " << fixed << setprecision(2) << total_present_price << " pounds" <<endl;

Kurt